An external cable system for a floating wind turbine generator

Abstract

This invention discloses an external cable system for a floating wind turbine generator, comprising: a main cable, a stress relief device, a monitoring system, a main cable rigid spacer, auxiliary cables, and a lightning protection system. The stress relief device connects the main cable to the floating wind turbine generator at both ends, preventing bending stress caused by large angles at the root of the main cable under vibration, self-weight, and wind load conditions, thus avoiding the problem of insufficient lifespan of the main cable. This system is applicable to dual-head floating wind turbine generators and existing single-head floating wind turbine generators, ensuring stable connections between the components of the wind turbine generator and simultaneously solving the lifespan, resonance, and lightning protection problems in existing technologies.

Description

Technical Field

[0001] This invention relates to the technical field of cable structures for floating wind turbine generators, and in particular to an external cable system for floating wind turbine generators. Background Technology

[0002] Existing technologies related to cable anchoring and cable-stayed towers for floating wind turbine generators have disclosed cable end fixing structures, some of which employ a figure-eight-shaped universal joint structure. These structures also disclose cable length adjustment methods such as hydraulic cylinder adjustment, base position adjustment, and threaded adjustment. However, base position adjustment has limited range for correcting cable installation length deviations, and hydraulic cylinder adjustment structures are difficult to withstand long-term cable loads. Threaded adjustment solutions are mostly simple pin connections, and the integration and reliability of the cable pre-tensioning and length adjustment structures still have room for improvement. Furthermore, these cable-related technologies are mostly applied to single-tower wind turbine structures and lack specific design for cable systems in single-floating, dual-head wind turbines. They also lack systematic solutions to engineering problems encountered in actual operation, such as frequency resonance, fatigue damage, cable stress monitoring, installation adjustment, and lightning protection.

[0003] Existing cable-stayed vibration damping devices mostly use rubber elastomer structures, which have problems such as high cost, inconvenient installation, maintenance and replacement, and small deflection adjustment angle due to the limitations of the elastomer's shear characteristics. Although the publicly disclosed floating foundation and multi-blade wind turbine technologies mention cable arrangement, they do not provide detailed design of the cable system structure and lack supporting structures such as auxiliary cables and rigid spacers.

[0004] Existing cable-stayed lightning protection systems only cover a portion of the cable layout, resulting in complex installation procedures and difficulty in achieving full-range lightning protection. Currently used cable anti-collision devices are external, full-circle structures, requiring the anti-collision pipes to be pre-installed on the outside of the cable, which is inconvenient for transportation and on-site installation. Existing swing-type and self-adaptive rigid bulkhead structures suffer from drawbacks such as fixed interfaces, difficult installation, and excessive weight, failing to meet the requirements for efficient assembly and long-term stable operation of offshore cable-stayed systems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and propose an external cable system for floating wind turbine generators. Applied to both dual-head floating wind turbine generators and existing single-head floating wind turbine generators, this system ensures stable connections between the various components of the wind turbine generator and simultaneously solves problems related to lifespan, resonance, and lightning protection in existing technologies.

[0006] The objective of this invention is achieved through the following technical solution: an external cable system for a floating wind turbine generator, comprising: The main cable, which consists of multiple sets, is installed between the main unit and the floating foundation of the floating wind turbine generator set, between the towers, and between the towers and the floating foundation, respectively, for tensioning the main unit, the towers, and the floating foundation; wherein, the main cable has a tensioned end and a non-tensioned end, and the main cable includes a cable core, an inner sheath, and an outer sheath arranged from the inside to the outside; A stress relief device is installed at the connection between the main cable and the host, tower and floating foundation. It is used to release the angular torque caused by the rotation of the main cable and to adjust the overall length of the main cable. The monitoring system includes a data acquisition station, a magnetic flux sensor, and a vibration sensor, used to monitor the cable force and frequency of the main cables in real time. The data acquisition station is installed in the nacelle of the floating wind turbine and communicates with the control system of the floating wind turbine. The magnetic flux sensor and vibration sensor are installed on each set of main cables and communicate with the data acquisition station. The data acquisition station integrates a switchboard, an industrial switch, a serial server, a dynamic acquisition system, and a flux meter.

[0007] Furthermore, the system includes: Main cable spacers are installed on each group of main cables to separate the main cables and adjust their frequency. Auxiliary cables are installed between the main cables and the tower to form a cable net, which is used to adjust the frequency of the main cables; A lightning protection system is installed at the main cable to prevent the main cable from being struck by lightning.

[0008] Furthermore, the core cable is a steel wire or steel strand core cable, and both the inner and outer sheaths are filled with anti-rust grease.

[0009] Furthermore, the tensioning end of the main cable is designed with a threaded anchor head, and the threaded anchor head is equipped with multiple washers. The length of the tensioning end is adjusted by the threads of the threaded anchor head and the number of washers. The non-tensioning end of the main cable is designed with a hinge lug.

[0010] Furthermore, the stress relief device includes a universal joint and a bearing. The universal joint has a figure-eight shaped structure, with its two ends having horizontal planes perpendicular to each other and connection holes respectively. The hinge lugs of the main cable, the tower, and the floating foundation are detachably connected to the universal joint through the connection holes. The bearing is an elastic bearing, which includes a first spherical component and a second spherical component. A rubber sheet with buffering and shock absorption functions is bonded between the first spherical component and the second spherical component. The elastic bearing is sleeved on the outside of the threaded anchor head of the main cable and forms a detachable connection with the main cable.

[0011] Furthermore, the universal joint is connected to an anchor chain and an anchor chain length adjuster. One end of the anchor chain is connected to the hinge of the main cable, and the other end of the anchor chain is connected to the connection hole of the universal joint. The anchor chain length adjuster is installed on the anchor chain.

[0012] Furthermore, the universal joint's connection hole is an elongated hole extending along the length of the universal joint. An adjustable component is detachably fitted inside the elongated hole to adjust its length. The elongated hole is connected to the hinge of the main cable.

[0013] Furthermore, the universal joint has multiple connection holes, all arranged along the length of the universal joint, and each connection hole can be connected to the lug of the main cable for adjusting the installation length.

[0014] Furthermore, the lightning protection system includes a lightning protection wire, a lightning protection copper mesh, and a lightning rod. The lightning protection wire is installed on the upper part of the main cable, the lightning protection copper mesh is installed between the inner sheath and the outer sheath, and the lightning rod is installed on the outside of the main cable and is equipped with a ground wire.

[0015] Furthermore, the magnetic flux sensor is sequentially connected to the switchboard, the flux meter, the serial server, and the industrial switch; the vibration sensor is sequentially connected to the dynamic acquisition system and the industrial switch; the data acquisition station integrates an air switch and a leakage current protector; and the flux meter, the serial server, and the dynamic acquisition system are connected to a preset external power supply through the air switch and the leakage current protector.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Due to the impeller's rotation frequency, in order to avoid resonance between the rotation frequency and the cable's natural frequency, the cable's natural frequency needs to be greater than 1Hz, while the steel cable's natural frequency is less than 1Hz. This invention uses a main cable spacer and auxiliary cables to increase the main cable's natural frequency.

[0017] 2. The present invention uses stress relief devices at both ends of the main cable to connect with the floating wind turbine generator, which avoids the problem that the main cable cannot meet the service requirements due to bending stress caused by a large angle at its root under vibration, self-weight and wind load.

[0018] 3. The stress relief device of the present invention also has the function of length adjustment, which solves the practical technical problem that the cable installation needs to be compensated for due to the error in the production of large components.

[0019] 4. The present invention has a monitoring system that can prevent abnormal tension and frequency of the main cable from causing damage to the main cable.

[0020] 5. This invention has a lightning protection system that can prevent the main cable from being damaged by lightning strikes. Attached Figure Description

[0021] Figure 1 A schematic diagram of the installation structure of the main cable and auxiliary cables.

[0022] Figure 2 This is one of the structural diagrams of the main cable.

[0023] Figure 3 This is a schematic diagram of a universal joint.

[0024] Figure 4 This is one of the schematic diagrams of the connection hole structure of a universal joint.

[0025] Figure 5 A cross-sectional view of the main cable.

[0026] Figure 6 This is a communication logic diagram for the monitoring system.

[0027] Figure 7 This is the second schematic diagram of the universal joint's connection hole structure.

[0028] Figure 8 This is the third schematic diagram of the universal joint's connection hole structure.

[0029] Figure 9 The second structural diagram of the main cable.

[0030] Figure 10 This is a schematic diagram of the sliding bearing and elastic support assembly.

[0031] Figure 11 This is a schematic diagram of the gasket structure. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments. Example 1

[0033] See Figures 1 to 6 As shown, the external cable system for the floating wind turbine generator provided in this embodiment is applied to a dual-head floating wind turbine generator and includes: 1) Main cables a: There are six sets of main cables a, which are respectively installed between the main unit 13 and the floating foundation 11, between the tower 12, and between the tower 12 and the floating foundation 11 of the floating wind turbine generator set, to tension the main unit 13, the tower 12, and the floating foundation 11. In this embodiment, the four sets of main cables are the upper left wind direction cable 1, the upper right wind direction cable 2, the upper horizontal cable 3, the lower horizontal cable 4, the lower left wind direction cable 5, and the lower right wind direction cable 6; wherein, the main cables have tensioned ends and non-tensioned ends. The tensioned ends of the main cables are designed with threaded anchor heads a2, and the threaded anchor heads a2 are equipped with washers, see [reference]. Figure 11As shown, the gasket is preferably a segmented gasket i, and each segmented gasket i has a mutually cooperating concave-convex structure i1\i2 so that the segmented gaskets i can fit tightly together without relative slippage. Every four segmented gaskets i form a group, and each group of segmented gaskets i is set around the threaded anchor head a2. The segmented gaskets of each group can be set to different thicknesses to precisely adjust the length of the threaded anchor head a2. In summary, the length of the tensioning end is adjusted by the thread of the threaded anchor head a2 and the number of groups of segmented gaskets i. According to the actual installation requirements, the main cable needs to be tensioned at the top, i.e., the main host end. Therefore, the tensioning end of the main cable is connected to the main host 13, and the non-tensioning end of the main cable is connected to the tower 12 and the floating foundation 11.

[0034] The main cable a includes a core m, an inner sheath o, and an outer sheath p arranged from the inside out. The core m is a steel strand core with a pre-coated galvanized epoxy coating. Both the inner sheath o and the outer sheath p are filled with anti-rust grease n. Because the steel strand core is spirally braided, it forms a certain barrier, allowing the anti-rust grease n to remain inside the inner sheath o and the outer sheath p, preventing it from flowing out along the steel strand core. Preferably, the inner sheath o is made of HDPE material, and the outer sheath p is made of polyurea material.

[0035] 2) Stress relief device: The stress relief device is installed at the connection between the main cable and the host 13, the tower 12 and the floating foundation 11. It is used to release the angular torque caused by the rotation of the main cable and to adjust the overall length of the main cable. The stress relief device includes a universal joint b and a bearing. The universal joint b has a figure-eight shaped structure. The two ends of the universal joint b are perpendicular to each other and each has a connection hole. The hinge lug a1 of the main cable, the tower 12, and the floating foundation 11 are detachably connected to the universal joint b through these connection holes. One end of the universal joint b has a long, narrow hole b1 extending along its length. An adjustable component is detachably installed inside the long, narrow hole b1. In this embodiment, the adjustable component is a movable pad b2, which can move along the length of the long, narrow hole b1 to adjust its length. The long, narrow hole b1 is connected to the hinge lug a1 of the main cable. The other end of the universal joint b is connected to the tower 12 and the floating foundation 11 via a pin d. The bearing is an elastic bearing c, which includes a first spherical component and a second spherical component. A rubber sheet with buffering and shock absorption functions is bonded between the first and second spherical components. The elastic bearing c is sleeved on the outside of the threaded anchor head a2 of the main cable and forms a detachable connection with the main cable. For the left upper wind direction cable 1, right upper wind direction cable 2, left lower wind direction cable 5, and right lower wind direction cable 6, if the non-tensioned ends of these four types of main cables are not equipped with bearings, hinge lugs a1 are designed as a substitute.

[0036] 3) Main cable spacer 7, which is installed on the left upper wind direction cable 1, right upper wind direction cable 2, upper horizontal cable 3, lower horizontal cable 4, left lower wind direction cable 5 and right lower wind direction cable 6, and is used to separate the main cables and adjust the frequency of the main cables; 4) Auxiliary cables: Auxiliary cables are installed between the main cable and the tower 12 to form a cable net. In this embodiment, the auxiliary cables are left auxiliary cable 8, right auxiliary cable 9 and horizontal auxiliary cable 10, which are used to adjust the frequency of the main cable. 5) Lightning protection system: The lightning protection system is installed at the main cable to prevent the main cable from being struck by lightning. The lightning protection system includes lightning protection wire, lightning protection copper mesh and lightning rod. The lightning protection wire is installed on the upper part of the main cable, the lightning protection copper mesh is installed between the inner sheath and the outer sheath, and the lightning rod is installed on the outside of the main cable and is equipped with a ground wire.

[0037] Preferably, a lightning protection system is added to the left-upwind cable 1, right-upwind cable 2, and upper horizontal cable 3. Cable clamps and lightning rods are installed at predetermined intervals, and every two lightning rods are connected by a lightning protection grounding wire. The lightning protection grounding wire is spirally wound multiple times on the cable body, distributing its weight across the cable body and preventing damage to the joints due to the weight of the wire. The lightning protection grounding wire is fixed to the cable body with clamps, and there is also a jumper connection between two cable bodies to prevent the lightning protection grounding wire between two lightning rods from falling off. A heat insulation layer is added under the lightning protection copper mesh to prevent excessive local heat from damaging the inner sheath. At the same time, multiple metal lightning interception points are arranged on the cable body, and the lightning protection copper mesh and the lightning interception points form a multi-point connection.

[0038] 6) Monitoring System: The monitoring system includes a data acquisition station, magnetic flux sensors, and vibration sensors for real-time monitoring of the tension and frequency of the main cables. The data acquisition station is installed in the nacelle of the floating wind turbine and communicates with the control system of the floating wind turbine. The magnetic flux sensors and vibration sensors are installed on each set of main cables and communicate with the data acquisition station. The data acquisition station integrates a switchboard, industrial switch, serial server, dynamic acquisition system, and fluxmeter. The magnetic flux sensors communicate sequentially with the switchboard, fluxmeter, serial server, and industrial switch; the vibration sensors communicate sequentially with the dynamic acquisition system and industrial switch. The data acquisition station integrates an air switch and a leakage current protector. The fluxmeter, serial server, and dynamic acquisition system are connected to a preset external power supply through the air switch and leakage current protector. Example 2

[0039] See Figure 7 As shown, the floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that the universal joint has multiple connection holes b4, all arranged along the length of the universal joint. Each connection hole can be connected to the hinge of the main cable for adjusting the installation length; the distance between two connection holes is L2-L1. Example 3

[0040] See Figure 8 As shown, the floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that the universal joint connection hole is an elongated hole extending along the length of the universal joint. An adjustable component is detachably installed inside the elongated hole. The adjustable component is preferably a bushing b3, which is embedded in the inner wall of the elongated hole and used to adjust the length and width of the elongated hole. Example 4

[0041] The floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that the universal joint is connected to an anchor chain and an anchor chain length adjuster. One end of the anchor chain is connected to the hinge lug of the main cable, and the other end of the anchor chain is connected to the connection hole of the universal joint. The anchor chain length adjuster is installed on the anchor chain, and the anchor chain length adjuster is preferably a chain reel. Example 5

[0042] See Figure 9 As shown, the floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that both the tensioned end and the non-tensioned end of the main cable a are designed with threaded anchor heads, and each threaded anchor head is equipped with an elastic bearing c. Example 6

[0043] The floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that both the tensioned and non-tensioned ends of the main cable are designed with hinges, and universal joints are installed on the hinges. Example 7

[0044] The floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that the tensioning end of the main cable is provided with a steel strand clamp, and the non-tensioning end is designed with a hinge, and the hinge is equipped with a universal joint. Example 8

[0045] The floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that the cable core is made of parallel woven fiber core, resulting in a small diameter main cable with high structural strength. Example 9

[0046] See Figure 10 As shown, the floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that the elastic bearing is replaced by a combination of a sliding bearing and an elastic support assembly. The sliding bearing includes an outer ring f and an inner ring e. The lower part of the outer ring f is detachably connected to the elastic support assembly g. The lower part of the elastic support assembly g is connected to an installation component h. The advantage of using this structure is that if one component is damaged, only the damaged component needs to be replaced. At the same time, the rotation angle of the sliding bearing is larger than that of the elastic bearing. Example 10

[0047] The floating wind turbine external cable system provided in this embodiment differs from that in Embodiment 1 in that, according to actual installation requirements, if the main cable needs to be tensioned on the water surface, the tensioned end of the main cable is connected to the tower 12 and the floating foundation 11, and the non-tensioned end of the main cable is connected to the main unit 13. Example 11

[0048] The floating wind turbine generator external cable system provided in this embodiment differs from that in Embodiment 1 in that both ends of the upper horizontal cable are equipped with bearings, preferably elastic bearings. The elastic bearings are sleeved on the outside of the threaded anchor head of the upper horizontal cable and form a detachable connection with the upper horizontal cable. At this time, both ends of the upper horizontal cable can actually be tensioned. According to the actual installation requirements, any end of the upper horizontal cable can be selected as the tensioning end.

[0049] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Therefore, all changes made in accordance with the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. An external cable system for a floating wind turbine generator, characterized in that, include: The main cable, which consists of multiple sets, is installed between the main unit and the floating foundation of the floating wind turbine generator set, between the towers, and between the towers and the floating foundation, respectively, for tensioning the main unit, the towers, and the floating foundation; wherein, the main cable has a tensioned end and a non-tensioned end, and the main cable includes a cable core, an inner sheath, and an outer sheath arranged from the inside to the outside; A stress relief device is installed at the connection between the main cable and the host, tower and floating foundation. It is used to release the angular torque caused by the rotation of the main cable and to adjust the overall length of the main cable. The monitoring system includes a data acquisition station, a magnetic flux sensor, and a vibration sensor, used to monitor the cable force and frequency of the main cables in real time. The data acquisition station is installed in the nacelle of the floating wind turbine and communicates with the control system of the floating wind turbine. The magnetic flux sensor and vibration sensor are installed on each set of main cables and communicate with the data acquisition station. The data acquisition station integrates a switchboard, an industrial switch, a serial server, a dynamic acquisition system, and a flux meter.

2. The external cable system for a floating wind turbine generator according to claim 1, characterized in that, include: Main cable spacers are installed on each group of main cables to separate the main cables and adjust their frequency. Auxiliary cables are installed between the main cables and the tower to form a cable net, which is used to adjust the frequency of the main cables; A lightning protection system is installed at the main cable to prevent the main cable from being struck by lightning.

3. The external cable system for a floating wind turbine generator according to claim 1, characterized in that, The core cable is a steel wire or steel strand core cable, and both the inner and outer sheaths are filled with anti-rust grease.

4. The external cable system for a floating wind turbine generator according to claim 1, characterized in that, The tensioning end of the main cable is designed with a threaded anchor head, which is equipped with multiple washers. The length of the tensioning end is adjusted by the threads of the threaded anchor head and the number of washers. The non-tensioning end of the main cable is designed with a hinge lug.

5. The external cable system for a floating wind turbine generator according to claim 4, characterized in that, The stress relief device includes a universal joint and a bearing. The universal joint has a figure-eight shaped structure. The two ends of the universal joint are perpendicular to each other and are respectively provided with connection holes. The hinge lugs of the main cable, the tower, and the floating foundation are detachably connected to the universal joint through the connection holes. The bearing is an elastic bearing, which includes a first spherical part and a second spherical part. A rubber sheet with buffering and shock absorption functions is bonded between the first spherical part and the second spherical part. The elastic bearing is sleeved on the outside of the threaded anchor head of the main cable and forms a detachable connection with the main cable.

6. The external cable system for a floating wind turbine generator according to claim 5, characterized in that, The universal joint is connected to an anchor chain and an anchor chain length adjuster. One end of the anchor chain is connected to the hinge of the main cable, and the other end of the anchor chain is connected to the connection hole of the universal joint. The anchor chain length adjuster is installed on the anchor chain.

7. The external cable system for a floating wind turbine generator according to claim 5, characterized in that, The universal joint connection hole is an elongated hole extending along the length of the universal joint. An adjustable component is detachably fitted inside the elongated hole to adjust its length. The elongated hole is connected to the hinge lug of the main cable.

8. The external cable system for a floating wind turbine generator according to claim 5, characterized in that, The universal joint has multiple connection holes, all arranged along the length of the universal joint. Each connection hole can be connected to the hinge of the main cable for adjusting the installation length.

9. The external cable system for a floating wind turbine generator according to claim 2, characterized in that, The lightning protection system includes a lightning protection wire, a lightning protection copper mesh, and a lightning rod. The lightning protection wire is installed on the upper part of the main cable, the lightning protection copper mesh is installed between the inner and outer sheaths, and the lightning rod is installed on the outside of the main cable and is equipped with a ground wire.

10. The external cable system for a floating wind turbine generator according to claim 1, characterized in that, The magnetic flux sensor is sequentially connected to the switchboard, the flux meter, the serial server, and the industrial switch. The vibration sensor is sequentially connected to the dynamic acquisition system and the industrial switch. The data acquisition station integrates an air switch and a leakage current protector. The flux meter, the serial server, and the dynamic acquisition system are connected to a preset external power supply through the air switch and the leakage current protector.

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